CREATE OR REPLACE VIEW search_orders AS 
   SELECT purchase_order.id AS id,
      purchase_order.jsonb AS jsonb,
      po_line.jsonb ||
      COALESCE(purchase_order.jsonb, '{}'::jsonb) AS metadata
   FROM po_line
      LEFT JOIN purchase_order ON (po_line.jsonb -> 'purchase_order_id'::text) = (purchase_order.jsonb -> 'id'::text);